Hydraulic well jar



Novi 14, 1939. c H. coLLETT HYDRAULIC WELL JAR original Filed Aug. 28, 1936 Illu Patented Nov. 14, 1939 UNITED STATES PATE/NT OFFICE HYDRAULIC WELL JAR Charles H. Collett, Walnut Park, Calif., assigner of one-half to Harry E. Lynn, Monterey Park,

Calif.

s claims.

This invention relates to oil well tools, and particularly pertains to a hydraulic well jar, and is a continuation of my application entitled Hydraulic well jar, Serial Number 98,328, led by me August 28, 1936.

In the operation of various drilling equipment, especially those used in oil wells,.it is often the practice to include aset of well jars in the drillstring so that in the event the drill bit or the string becomes fastened accidentally in the hole it will be possible to impose a jarring action upon the drill-string tending to loosen the fastened parts. It is usual practice to temporarily hold` the relatively moving parts of the jar in extended relation to each other and to rely upon Various mechanical means for thus temporarily holding the parts, and for suddenlly releasing them so that -their impact faces may engage each other and thus produce a sudden jarring blow.

Due to the fact`that the tensile strain imposed upon the parts of the jar is of great magnitude it will be recognized that the locking and jarring means will be subject to damaging wear. It is also common practice to provide well jars with releasing means which operate as a result of or in resistance to torsional strain imposed upon or maintained within a drill-string. This of course subjects each threaded joint in the drill-string to a force which in one direction of rotation tends while insuring that a direct blow will be struck` between the hammer and the anvil as produced bylongitudinal stress only.

40 The present invention contemplates the provision of a jar barrel and a mandrel, the barrel Y forming hydraulic cylinders, and the mandrel carrying pistons adapted to displace uid from one cylinder to the other, said mandrel and bar- 45 relcarrying impact members by which a jarring blow is created when they come into physical contact.

in the accompanying drawing in which:

Figure l is a View in central longitudinal section showing the parts of the jar in a set tion priory to delivering the blow.

Fig. 2 is a view in central longitudinal section through the jar showing the parts of the jar in 55- impact position.

to loosen the threaded joints of the string. It is The invention is illustrated by way of example posi- Fig. 3 is a view in transverse section through the jar as seen on the line 3--3 of Fig. 1, showing the splined connection between the jar barrel and the mandrel.

Fig. 4 is a view in transverse section through x the jar as seen on the line 4 4 of Fig. 1, showing the construction of the valve seat. y

Fig. 5 is an enlarged fragmentary View showing the valve construction.

Referring more particularly to the drawing, II) indicates a threaded box of a drill string. A threaded bore II is formed in the lower opened end of a jar barrel I2 and receives the threaded pin, The jar barrel I2 is formed in two longitudinally aligned cylindrical sections I3 and I4. The upper section is connected to the lower section by a coupling element I5 which has anupper threaded portion I6 and a lower threaded portion i'I. The upper threaded portion receives the lower threaded end of the section I3 and the lower threaded portion II receives the upper threaded end of the cylindrical section I4. The upperlend of the cylindrical section I3 is here shown as carrying an anvil bushing I8 which is threaded into the upper end of the section. This bushing is provided with a central opening I9 through which the upper end 2D of a mandrel 2I extends. The mandrel is provided with a pin 'I2 which may be threaded into an upper drill joint. The upper section 2lil of the mandrel carries splines 23 vertically sliding in longitudinally extending keyways 24 formed in the wall of the bore I9 of the anvil section IB.L It is to be understood that the anvil section might be formed integral with the upper barrel section I3 if desired. The coupling I5 substantially forms a partition between the barrel sections I3 and I4 and vthereby creates an upper hydraulic cylinder 25 and a lower hydraulic cylinder 26. The lower end of the coupling I5 is-iormed withfa transverse valve seat 21 having a central passageway 2 8 therethrough. Threaded or `pressed into the circular bore of the passageway 28 is a bushing 29. Reciprocating through this bushing 29 is the upper reduced end 30- of the mandrel 2|. Attention is directed to the fact that an annular space 3| occurs between the circumferential surface of the portion 30 of the mandrel and the inner face of the bushing 29. This is a fluid space,`thelwidth of which is determined and selected for a purpose to be hereinafter described. ExtendingA down through the valve seat portion 2l of the coupling I5 is a plurality of fluid passageways 32 which under certain conditions establish communication between the displacement vcylinder 25 and the displacement cylinder 26. These passageways are formed with a counter-bore 33 at their lower ends within which valve balls 34 are mounted. These-balls will be heldin their uppermost positions to seal the passageways 33 when influenced by the pressure of fluid within the cylinder 26. Disposed beneath the counter-bores 33 and adapted to completely cover these counter-bores when lying thereagainst is afvalve disc 35. This disc is free to move vertically within asz'ounter-bore 36 of the cylinder 26, thus it is limited in its downward movement, and when pressure is exerted against it it will seat against the end face of the coupling |5 and seal the counter-bores 33 and their passageways 32. When this pressure is discontinued thedisc 35 and the valve balls 34 will fall away from their seats and re-establish communication through the passageways 32. The lower end of the reduced portion 30 of the mandrel 2| is formed with a reduced extension 38 terminating at its lower end with a shoulder 39. Mounted upon an extension 38 and seated against the shoulder 39 is a piston body 40. 'Ihe upper end of this body terminates in an annular flange portion 4| providing a seat for the upwardly presented lip of a cup washer 42. Mounted below the cup washer 42 of the body 40 is a spacing washer 43 below which a cupwasher 44 with a downwardly presented lip fits around a packing washer 45. Mounted directly below the packing washer 45 is a wiper washer 46. This washer may be made of soft metal or suitable non-metallic material, and fits against the wall of the cylinder 26 to clear it of gritty material, such as sand. A metallic fastening washer is mounted upon the portion 38 of the mandrel and overhangs the lower end of the piston body member 40, the outside diameter of the washer substantially agreeing with the ouside diameter of the upper portion 4| of the piston body. Lock nuts 48 and 49 are secured upon the threaded portion 50 at the lower end of the mandrel 2| and hold the assembled structure of piston 5| upon the mandrel. An upper piston 52 is mounted upon a length 53 of the mandrel and has the same parts as the lower piston 5|, save that the'parts are inverted in their arrangement and rest upon a hammer collar 54 formed upon the upper length 20 of the mandrel. These piston elements are held in this position by a lock nut 55. Attention is directed to the fact that the diameter of the intermediate length 38 of the mandrel is less than the diameter of the bushing 29, and that the diameter of the length 36 of the mandrel 2| is a predetermined amount smaller in diameter than that of the bushing 29 to cause a transverse space 56 to occur between the wall of the central bore 51 of the valve disc 35 and the circumferential surface of the mandrel length 38 when the jar barrel moves toward its uppermost position.

By reference to Fig, l of the `drawing it will be seen that the drill pipe indicated at limits the collapsed position of the jar when it abuts against the upper face of the anvil section |8, thus a direct downward force may be exerted upon the entire structure when desired without imposing any undue strain upon the jar mechanism. Attention is also directed to the fact that a central fluid circulation opening 59 extends entirely through the mandrel 2| and that in communication with theupper cylinder 25 are fluid ports 60 which are formed through the upper wall section I3 of the barrel I2.

By reference to Fig. l it will be seen that when the mandrel 20 is in its lowermost position within the barrel that the mandrel section 30 will be projecting through the bushing 29 and that an annular by-pass space 3| will occur between the circumference of the bore of the bushing and the outer circumference of the portion 30 of the mandrel. At the same time a larger by-pass space 51 will occur through the valve element 33 and around the reduced portion 38 of the mandrel.

In Fig. 1 of the drawing the fluid space 26' is indicated as occurring between the partition member I5 and the lower piston 5|, and in Fig. 2 of the drawing an upper fluid space 25 is shown as occurring between the partition element |5 and the upper piston 52. It has been found desirable to construct the well jar so that the volumetric capacity of the upper fluid space 25 shall always be greater than the volumetric capacity of the lower fluid space 26. This insures that at all times there will be sufficient fluid in the cylinder 26 to produce a hydraulic lock for the jar and hold it with the hammer and anvil in positions preparatory to striking in a jarring action.

In operation of the present invention the element I0 is connected to a suitable fishing tool which tool is in turn placed in engagement with the fish. A desired purchase is then taken on the drill-string to place the structure under tension, as is usual in well jarring operations. At this time the piston 5| is in its lowermost position with relation to the intermediate partition member |5 and the piston 52 is in its lowermost position within the cylinder 25. A quantity of oil or other incompressible fluid now'flllsv the space 26 in the cylinder 26, and the valve ring 35and the valve balls 34 are in their uppermost positions to seal the ports 32 through the valve seat structure 21 of the intermediate partition |5. IAt this time the portion 30 of the mandrel 2| is in its lowermost position and extends through the bushing 29 so that the relatively narrow annular by-pass space 3| occurs therearound. A. pull will be exerted on the piston 5| as created by the tension placed in the drill-string incident to the jarring operation and during which timethe drill-string has been stretched and tends to restore itself to its original non-'stretched condition. The tension pull upon the piston' 5| will draw it upwardly and will displace the fluid in the space 26',v A

which fluid is forced through the restricted annular orce 3|. As a result of this displacement the portion 30 of the mandrel will be drawn gradually through the bushing 29 until the lower end of the length 30 of the mandrel has been drawn upwardly through the partition portion of the member I5, after which the mandrel section 38 of reduced diameter wlll'be in register with the orifice 3| which orifice willthen be enlarged so that the remaining fluid within the space 26' of the cylinder 26 will be suddenly discharged into the space 25 of the cylinder 25. This increased volume of' fluid will be accommo- 7 dated in the space'25' since the piston 52 simulfrom the supporting drill-string and then loweringthe mandrel 2l within the barrel I2. In doing this the piston Il will be lowered into cylinder 26 and the piston 62 will be lowered into cylinder 25. This lowering action will cause the piston 52 to force the incompressible uld from he space in the cylinder 28 into the space 26' in the cylinder 26, which downward ilow will be very easily accomplished so long as the length 38 of the mandrel 2l is in register with the opening through the bushing 29, after which further force will act through the valve ports 32 to lower the valve balls 24 and the valve ring 35 and thus increase the by-pass area after the enlarged section of the mandrel has entered the bushing 29. As the piston 52 reaches the lower end of its stroke the drill pipe 55 will engage the upper face of the partition member I5 and prevent further downward movement of the mandrel. At this time the valve ball 24 and the valve ring 35 are seated due to the compressed iluid within the space 26'. A new jarring stroke may then be negotiated.

Attention is again directed t0 the fact that the parts not subject to excessive wear, and which insure that the jar will operate by direct tension strain without the necessity of applying torque to the jar mechanism orto the drill-string, it

` further being evident that the magnitude of the jarring blow will be directly controlled from the top of the well, and that jarring action will be applied in a direct pull upon the object to be dislodged without danger of loosening the iishing tool.V It will further be evident that when necessary the drill-string can be rotated due to the splined connection between the mandrel and the sleeve, and that finthermore, the circulation of drilling uid may be maintained through the jar at all times.

While I have shown the preferred i'orm o1' my invention, as now known to me, it will be understood that various changes might be made in the combination, construction, and arrangement of parts, by those skilled in the art, without de-V parting from the spirit of the invention as claimed.

Having thus described my invention, what I l. A well jar comprising a tubular barrel, a mandrel longitudinally reciprocating therein, a

transverse partition in the barrel and through which the mandrel extends, a pair of pistons xed upon the mandrel in spaced relation to the transverse partition and whereby alternate movement of the mandrel and its pistons will create a iiuid receiving compartment within the barrel and on opposite sides of the partition, a one-way valve associated with the partition and permitting the fiow of iiuid from one compartment to the other in one direction onlywhereby iuid may be entrapped in one compartment, impact members carried by the mandrel and the barrel and normally held apart by iluid entrapped in said compartment, and means eilected by forcelongitudinally applied to the mandrel and the barrel to cause the entrapped iluid to be displacedin the other fluid compartment and topermit the impact members to strike each other.

'Y 2. ,A well Jar comprising a tubular barrel, a transverse partition intermediate the ends thereof, said partition being formed with a central opening therethrough, a lmandrel longitudin/ally movable within the barrel and extending through said opening, said mandrel having a length of a diameter slightlyl less than the openin'g, and an adjoining length` having a diameter materially less than tlie opening through the partition, the

drst named length .of mandrel normally extending into said opening, a pair of pistons mounted upon the mandrel, one on each side of the partition, whereby relative longitudinal movement of the mandrel and the barrel will alternately create a fluid compartment upon opposite sides of the partition within the barrel, av one-way valvethrough the-partition permitting displacement of uid from one side of the partition to the other upon relative movement of the mandrel and the barrel and acting to entrap the iiuid between the partition and a mandrel piston at one side thereof, whereby the only exit ailorded for the entrapped fluid will be through the central opening and around the mandrel, and impact members carried by the barrel andthe mandrel respecv tively andmoving together upon relative longitudinal movement of the mandrel and the barrel when said mandrel and barrel have moved to a position where the mandrel section oi reduced diameter is in register-with the opening vthrough the barrel partition. A'

l 3. A well jar comprising' a tubular barrel adapted to be connected to an element of a drill-` string at one end, a mandrel longitudinally movable within the jar and connected to an element lof a drill-string at its outer end, a transverse partition disposed at a vpoint intermediate the ends oi' the barrel and dividing the barrel into two 'iluid receiving cylinders, an opening centrally of said .partition and through which the mandrel moves, saidl mandrel being formed with portions of dierent diameters, one diametersubstantially fitting the opening 'through the partition, and the other diameter being substantially less than the opening through` the partition, a pair of pistons carried upon the mandrel, one. on each side'of the partition-and-sospaced asato cooperate with the lpartition in; forming' a fluid?, receiving compartment.; upon alternate sides `or the partition as the mandrel 'and the barrel are moved to their extreme positions relative to eachy other, said enlarged mandrel section extending through the opening'inthe partition when the mandrel is in one extreme position, and s aid reduced mandrel section extending through-the opening in the partition as the mandrel moves to its other extreme position, a one-way valve through the partition to permit a flow of uid intoone of the iluid compartments only, and impact members normally held apart by the fluid within the last named uid compartment and released to move together as lthe reduced mandrel section moves into the opening through the partition.

4. In combination with a drill-string having longitudinal elasticity, a well jar. carried thereby having a pair of relative movable parts, impact members on each-of said parts, hydraulic means normally holding said impact members in spaced f relation to each other and means' acting when the drill string vis under longitudinal tension whereby the elasticity of the drill-string will act to airect the hydraulic means and release the same to allow a blow to be created between the impact members, said hydraulic means comprising a pair of iluid chambers created between the relative movable parts, a pair of pistons therefor having a common connecting means, an 'incompressible fluid within said chambers and means for establishing an independent flow of fluid from one of said chambers to the other.

5. A we ll jar comprising a tubular barrel, a mandrel longitudinally reciprocating therein, a transverse partition in the barrel and through which the mandrel extends, a pair of pistons ilxed upon the mandrel in spaced relation to the transverse partition and whereby alternate movement of the mandrel and its pistons will create a fluid receiving compartment within` the barrel on opposite sides of the partition, said fluid chambers containing an incompressible: fluid, means for establishing an independent flow of fluid between the chambers upon relative movement between the tubular barrel and the mandrel, impact members carried by the mandrel and the barrel and normally held apart by means of iluid entrapped in one of said fluid chambers, said relative movement between the barrel and the mandrel Causing the exchange of fluid from one chamber to the other whereby the impact members will strike each other,

6. In combination with a drill-string having longitudinal elasticity, a well jar carried thereby having a pair of relative movable parts, impact members on each of said parts, hydraulic means normally holding said impact members in spaced relation to each other'and means acting when the drill-string is under longitudinal tension whereby the elasticity of the drill-string will act to affect the hydraulic means and release the same to allow a blow to be created lbetween the impact members, said hydraulic means comprisw ing a pair of fluid chambers created between the relative movable parts, a pair of pistons therefor having a common connecting means, an incompressible fluid within said chambers and means for establishing an independent flow of fluid from 45 one of said chambers to the other, said cylinders being superimposed with relation to each other, the uppermost of said cylinders being of larger capacity than the lowermost of said cylinders.

7. In combination withla drill-string having longitudinal elasticity, a well jar carried thereby having a pair of relative movable parts, impact members on each of said parts, hydraulic means normally holding said impact members in spaced 6 relation to each other and means acting when the drill-string is under longitudinal tension whereby the elasticity of the drill-string will act to affect the hydraulic means and release the same to allow a blow to be created between the impact members, l0 said hydraulic means comprising a pair of fluid chambers created between the relative movable parts, a pair of pistons therefor having a common connecting means, an incompressible iluid within said chambers, means for establishing an inde- 15 pendent flow of fluid from one of said chambers to the other, said cylinders being superimposed with relation to each other, the uppermost of said cylinders being of larger capacity than the lowermost of said cylinders, and means for venting iluid 20 from the uppermost of said cylinders incident to the jarring action.

8. In combination With a drill-string having longitudinal elasticity, a well jar carried thereby having a pair of relative movable parts, impact 25 members on each of said parts, hydraulic means normally holding said impact members in spaced relation to each other and means acting when the drill-string is under longitudinal tension whereby the elasticity of the drill-string will act to affect 30 the hydraulic means and release the same to allow a blow to be created between the impact members, said hydraulic means comprising a pair of fluid chambers created between the relativemovable parts,\a pair of pistons therefor having'a common 35 connecting means, an incompressible fluid within said chambers and means for establishing an independent flow of fluid from one of said chambers to the other, said cylinders being superimposed with relation to each other, the uppermost of said 40 cylinders being of larger capacity than the lowermost of said cylinders, and meanslimiting the movement of the jar elements toward a collapsing position.

CHARLES H. COLLETT. 

